The present invention relates to a drilling rig in the form of a jack-up platform on which a cantilever is mounted so as to be movable at least substantially horizontally and in a first direction, with the cantilever projecting more or less outside the jack-up platform, while a Multi Purpose Tower is further present on the cantilever, said Multi Purpose Tower being movable relative to the jack-up platform in a second direction, different from the first direction.
In the conventional drilling rigs, the cantilever is movable only in its longitudinal direction relative to the jack-up platform, and the drilling platform is movable relative to the cantilever in a direction transverse thereto. Due to the resulting movement of the drilling platform relative to the jack-up platform, the drilling point of the drilling rig can reach any point located in a rectangle of which the lengths of the sides are determined by the travel of the cantilever relative to the jack-up platform and the travel of the drilling platform relative to the cantilever.
In the transverse direction, the distance between the cantilever beams, which determine the width of the cantilever, extending in the longitudinal direction limits the size of this rectangle. Located under the drilling platform is a grid of drilling points. The drilling platform with the blow-out valve and a part of the equipment, tools and materials for drilling that are further required moves from one drilling well to the other. As a consequence, the drilling pattern is limited to drillings within the rectangular shape.
A need has existed for a cantilever-drilling platform, which is more movable than these bidirectional platforms.
In the drilling rig according to the prior art (see patent no U.S. Pat. No. 6,171,027 for an example), the cantilever and tower are movable on load bearing plates and/or rollers, which are running over rails. These rails are fixed into the deck or are formed of a three-part housing that workers can trip over as they move along the deck. Accidents of all sorts have occurred with the presence of the rails or three part housings on the deck of the Jack Up rig. Furthermore these rails considerably limit the number of possible uses of the deck areas on which said rails are fixed.
In a drilling rig according to prior art a drilling derrick is fixable mounted on the cantilever. One of the properties of a drilling derrick is a large base needed for stability. This large base determines the minimum width of the cantilever and consequently the weight of the cantilever. A smaller width means a larger drilling area that can be reached and said drilling derrick limits the drilling area to a considerably content. Another disadvantage of a drilling derrick is the relative inaccessibility of the drill floor due to the large number of structural beams that are in the way. This severely limits the possible number of useful applications that can be performed on the drilling derrick.
A need exists for a cantilever with a drilling platform that does not have load bearing plates or rails or rollers so that that cantilever can move theoretically over whole deck of the jack up.
A need exists for a cantilever with a drilling platform that has a moving system for the cantilever that has fewer parts, thereby creating a unit that has lower maintenance cost and lower cost to construct.
A need also exists for a cantilever with a drilling platform that has one unit sliding bearings for two different directions to reduce friction between the cantilever and the deck.
A need also exists for a cantilever with a drilling platform that has a lower weight construction of cantilever and drilling tower, a smaller cantilever width, and an increased accessibility of the drill floor increasing the number of possible kinds of work that can be performed.
The invention herein is designed to satisfy the above-mentioned needs.
The invention relates to a Jack-Up drilling rig having a deck capable of being used offshore. The Jack-Up drilling rig is made of a cantilever that is mounted so as to be moveable in a first direction and a second direction, a Multi Purpose Tower fixably mounted on the cantilever, a supporting cart disposed between the cantilever and the deck of the Jack Up drilling rig, and at least four friction reducing devices.
The invention is also a method for installing drilling equipment on a sub-sea well and drilling the well using the Jack-Up drilling rig.
The invention is also a method for decommissioning a well using the Jack-Up drilling rig.